Foldable fin arrangement for a projectile



Feb. 9, 1960 J. R. JAssE' I 2,924,175

FOLDABLE FIN ARRANGEMENT FOR A PROJECTILE Filed Oct. 17, 1956 2 Sheets-Sheet l Feb. 9, 1960 JASSE 2,924,175

FOLDABLE FIN ARRANGEMENT FOR A PROJECTILE Filed Oct. 17, 1956 2 Sheets-Sheet 2 United States o FOLDABLE FIN ARRANGEMENT F OR A PROJECTILE Joseph Raymond Jasse, Paris, France, assignor to Soeiete Nouvelle des Etablissements Brandt, Paris, France, a French body corporate The present invention relates to foldable fin arrangements for projectiles and in particular fin arrangements for stabilizing self-propelled projectiles or rockets on their trajectory. The object of the invention is to provide a. fin arrangement which is simple, particularly convenient to use and very effective in use.

In this fin arrangement, each of the fins, which is mounted along one of its longitudinal edges on the central body of the fin arragement for pivotal movement about a longitudinal axis parallel to the axis of the fin arrangement, comprises at least two members connected together for pivotal movement about an axis parallel to said axes.

With this arrangement, when the fins are in their folded or closed position, in which their various members are closed against one another and against the central body of the fin arrangement, they take up very little space.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawing to which the invention is in no way limited.

In the drawing:

Fig. 1 is a rear end view of a fin arrangement, embodying the invention, in the unfolded or open position of the arrangement;

Fig. 2 is a partial side elevational view with a part of the body of the rocket, on which the fin arrangement is mounted, shown in section, and

Figs. 3 and 4 are similar views, the fin arrangement being in its folded or closed position.

In the illustrated embodiment, the fin arrangement is adapted to be fixed to the rear end of the hollow body R of a rocket or other projectile, this body being tapped at a for receiving the screw-threaded forward end 1 of the central body 2 of the fin arrangement. This body 2 is a body of revolution about a longitudinal axis XX (Fig. 2) which, after the body 2 has been screwed into the body R, coincides with the longitudinal axis of the projectile.

The body 2, which is hollow so as to form a nozzle 3 for ejection of the propelling gases, comprises a flange 4 and terminates at its rear end in a flange 5.

Pivoted to the body 2 are a number of fins--three in the presently-described embodiment-which are capable of being unfolded or opened in their operative positions A, B, C shown in Figs. 1 and 2, or folded or closed in their inoperative positions A, B C shown in Figs. 3 and 4.

Each fin comprises two members 6 and 7 which, in the unfolded fin position, are disposed adjacent one another substantially in a longitudinal radial plane containing the axis XX, whereas in the closed fin position they are closed one on top of the other and assume the positions 60 and 7a shown in Figs. 3 and 4.

The member 6 of each fin is pivoted to the body 2 by a pin 8 which is parallel to the axis XX, extends through the flange 4 of the body 2 and is engaged at its 2,924,175 Patented 9, 1960 forward end 9 in a blind hole formed in the forward part of the body 2, and at the rear end in a boss 10 provided on the flange 5 of said body. 1 r

The member 6 of the fin is pivotably mounted on the pin 8 by two eyes 11. "A coil spring 12 encompassing the pin 8 is arranged to work'under torsion so as to open or unfold the member 6 of the fin by pivoting it about the pin 8 in the direction of arrow f (Fig. 1) up to an extreme position shown in Fig. 1, one of the ends 13 of this spring bearing against the body 2 and its other end 14 bearing against the member 6. Furthermore, the spring 12 is arranged to work under compression since at one end it abutsthe flange 4 and at its other end it abuts the forward face 15 of the rear eye 11 of the member6ofthefin.

Thus the spring 12 urges the fin rearwardly relative to the projectile in the direction of arrow 1' (Fig. 2) and tends to engage thisfin inits unfolded position in a locked position resulting from the engagement of a recess 16 formed in the rear face of the eye 11, on a knifeedged part or like projection -17 formed on the forward face of the boss 10 (or vice-verse). The recess 16 and the projection 17 are so oriented that when the projection enters the recess, the member 6 of the fin lies in a substantially radial plane relative to the body 2.

The other member 7 of the fin is pivoted to the member 6 in a similar manner, that is, by means of a pin 18 which is also parallel to the axis XX. This pin 18 extends through conjugate eyes 19 and 20 formed on the members 6 and 7.

A spring 21 encompasses the pin 18 and also works, firstly, under torsion so as to unfold the member 7 of the fin by pivotal movement in the direction of arrow f relative to the member 6 (Fig. 1), the ends 22 and 23 of this spring bearing laterally against the members 6 and 7, and, secondly, under compression, since it bears against two of the eyes 19 and 20 and thus locks the member 7 to the member 6 in the unfolded position by engagement of a knife-edged part or like projection 24, formed on one of the eyes 20 of the member 7, in a recess 25 formed in the adjacent face of the adjoining eye 19 of the member 6 (or vice versa).

It will be noticed that one of the eyes 19, for example the rear eye 19 (Fig. 2), comprises an abutment 26 adapted to serve as a bearing face in the folded position 7a (see Fig. 3) of the member 7.

Before the projectile is launched, the fin arrangement is in the folded or closed position shown in Figs. 3 and 4. The two members of each fin are in their forward position, relative to the projectile, on their pivot pins 8 and 18 and their recesses 16 and 25 are disengaged from the locking means formed by the projections 17 and 24.

The fins are held in the folded position 6a, 7a in opposition to the actions of the springs 12 and 21 by a detachable ring 27 which is slipped over the folded fin arrangement in the forward direction relative to the projectile.

The projectile R, provided with the fin arrangement in its folded position, is engaged in the launching barrel and the ring 27 is automatically slipped off when it abuts the rear end of the launching barrel. The fins are temporarily held in their folded position while they are in side this barrel, but as soon as they issue therefrom they are automatically unfolded by the actions of the springs 12 and 21, each of which causes both the rotation of 3 16 and 25. Each fin 6-7 is thus locked in the unfolded or open position.

As is clearly shown in Fig. 3, the folded fin arrangement takes up a very small amount of space. Thus it is easily stored, whenmounted on "the projectile R, the fin arrangement dees not protrudefrom the Outer contour of the projectile (Fig. 3-) and thus does not interfere with the proper launching thereof. The automatic unfolding and locking of the fins by the action of the springs 12 and 21 ,rendersthe fin arrangement absolutely sure in operation.

Although a specific embodiment of the invention has been described, many; modifications and changes may be made therein without departing from the scope of the invention as defined in the accompanying claims. Thus the number of fins may be greater tha three and, if desired, each fin may consist of more than two members pivoted together in the above-described manner.

Having now described my invention what I claim as new and desire to secure by Letters Patent is:

A projectile comprising a central body defining a longitudinal axis, fins symmetrically distributed around said body, each fin including at least first and second planar members and hinge devices coupling the planar members and spaced longitudinally of each other, further hinge devices coupling the first planar members to said body, the hinge devices providing for a displacement of the parts whereby the first and second planar members can be flattened against each other and against said body, locking means on the hinge devices between associated planar members. and between one of the latter and said body, the locking means between the associated planar members and between said one of the latter and said body being on longitudinally spaced hinge devices; said locking means providing for locking the associated planar members in coplanar radial positions, and springs associated with each hinge device and acting with compressive and torsional forces respectively to actuate the locking means and to bring the planar members into radial position whereat the locking means are actuatable.

References Cited in the file of this patent UNITED STATES PATENTS 1,448,166 Strong Mar; 13, 1923 2,784,669 Apotheloz Mar. 12, 1957 FOREIGN PATENTS 1,096,579 France Feb. 2, 1955 1,104,534 France June 15, 1955 

